HELPPP!

I tested for trichomoniasis, chlamydia,Bacterial Vaginosis,Yeast Infection and Gonorrhea.THEY ALL CAME BACK NEGATIVE!!! BUT I CONTINUOUSLY HAVE A FISHY ONION SMELLY DISCHARGE.It is yellow too.I have taken 2 courses of oral metro and it would clear up for just for like 2 weeks and come right back WTF IS GOING ON WITH ME ???? IM TIRED IVE BEEN DEALING WITH THIS FOR YEARS. Probably since I was 12 years old I am now 18 years old and a broke college student I don’t have the funds to be running so many tests. I am beyond STRESSED:( What is causing this I don’t any other symptoms other than the yellow discharge with a foul smelling odor sometimes it smell overly sour! If I am to push my finger into my vagina and smell my finger it smells RAWWWW